Method for manufacturing artificial lumber



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METHOD FOR MANUFACTURING ARTIFICIAL LUMBEH Lamm 2 shee'is-sheet 1 Filed March '7, 1929 a m a .Il 9| sur@ 0000000@ @mi 24, lg H. w. BRQWN Er AL,

METHOD FOR MANUFACTURING ARTIFICIAL LUMBER 2 Sheets-Sheet 2 Filed March '7, 1929 Patented Oct. 24, 1933 ME'rnon Fon MANUFACTURING ARTIFICIAL Lumina Horatio W. Brown, Concord, and Melrose, Mass., asslgnors to Mass., a corporation of Delaware Inc., Boston,

Cyrus J. Taylor.' Bemis Industries.

Application March 7, 1929. Serial No. 345,077

.llclaima This invention relates to an improved method and apparatus for the manufacture of artincial lumber which comprises elongate strips or strands of material, e. g. excelsior or the like,

compacted and compounded together with appropriate binder which not only holds the strands in a firmly bound reticulated engagement but may also render the same substantially flre and moisture resistant.

able fibrous strands, such for example as ordinary excelsior, may be continuously formed into slabs, the material as received being brokenup and formed into a suitable loose uniform mat, being gradually compacted, receiving the cementitious material or binder, being compressed, formed into separate pieces or slabs and maintained under appropriate pressure while the cementitious material is allowed at least initially to set.

The present invention is particularly designed to permit the economical production of large quantities of material of this character having uniform qualities and particularly having its component strands uniformly and lightly coated with cementitious material. Experimentation has shown that it is diflicult to coat a fairly thick, somewhat compressed mass of tangled reticulated strands with cementitious material in such a manner that each of the strands is substantially uniformly yet thinly coated with the cementitious binder. Certain processes and modes of coating the fibrous material have resulted in the wasting of the cementitious material and clogging of irterstices thereof with solid masses of the set cement. This has resulted not only in wasting the binder but has objectionably 'affected the heat insulating efficiency and acoustic qualities of the ultimate product. On the other hand, insuiicient coating of some of the flbers results in a material which is not properly moisture or fire resistant, which does not afford a uniform surface and which does not have uniform mechanical strength, resistance to breakage, nailing qualities, or the like.

In accordance with the present invention, the strands of material preferably are uniformly distributed in a closed passage to form a loose mat. For this purpose we have found that the use of a blast of air is particularly effective. 'I'he loosely formed mat is then gradually compacted or compressed and delivered to a series of pairs of press and wringer rolls, the impregnating material being fed to the mat tovthoroughly coat 55 all its fibers, just as it passes between the rolls In accordance with the present invention suit-- section of the apparatus shown in Fig. 1;

(Cl. 15d- 2) which are adapted greatly to compress the material, the various parts of the apparatus being arranged not only so that the cementitious binder may drain through the mat but also so that the rolls may wring or squeeze the liquid from the e0 same; this arrangement results in the formation of a thin substantially uniform cementitious coating upon the individual strands. After leaving the wringer rolls the material may be permitted to expand somewhat, being then cut and delivered to suitable molds or to plates between which it is somewhat compressed until the cementitious material or binder has at least initially set.

In the accompanying drawings,

Fig. 1 is aside elevational view, somewhat diagrammatic in character, of a portion of the preferred form of apparatus;

Fig. 1l is a side elevational view of' another Fig. 1b is a similar view of a further section of the same; l

Fig. 2 is an elevational detail of the air nozzle, the control mechanism therefor and related Parts; so

Fig. 3 is a top view of a portion of the mechanism shown in Fig. 1*; y

Fig. 4 is a vertical section through a typical mold; and

Fig. 5 is a section on line 5 5 of Fig. 3.

Referring to the accompanying drawings, and more particularly to Figs. 1 and 1L thereof, it is to be understood that excelsior or the like is delivered to the apparatus from a suitable table 1 which may support a quantity of the excelsior as it is received from the manufacturing establishment with its strands or elements curled and quite firmly tangled and pressed together. This fibrous material is fed between rolls 3 and 4 one or both of which is provided with suitable feed projections 5 in order to deliver the material to a cutting mechanism 6. The latter is adapted to cut the long strands into somewhat shorter portions; for example, an average length of from two to six inches has been found commercially satisfactory. The cutting mechanism is provided with a rotor f1 having'knives 8 that are adapted to cooperate with a fixed plate 10 in shearing the strands and delivering the same to a suitable guide plate 13.

A conveyor belt 14 may carry the severed excelsior strands which are still in a more or less irregularly hunched, tangled condition to a picker l5 which comprises a roll 17 having radially disposed teeth 19 projecting therefrom and adapted to engage the bunched encelsior portions and to 110 cooperate with a comb 18u carried by a curved cover plate 18 in loosening the same. From the picker 15 the material preferably falls into an inclined passageway or chute 25. At this portion of the mechanism, we preferably provide suitable means evenly to distribute the fibrous strips to make a substantially uniform, loose or fluffed mat. 'While various expedients may be found satisfactory for this end, we prefer to provide a movable air pressure nozzle 27 which projects downwardly into the inlet or upper end of the passage 25 and which is moved transversely across this passage by mechanism disclosed more particularly in Fig. 2.

For this purpose the axle 81 of roll 1'1 may be provided with an eccentric pin 83, one end of a link 84 engages this pin and the opposite end of the link is connected to a bell crank 85 which in turn is articulated to a transverse rod 86, the latter being pivotally connected to the nozzle support 87; thus rotation of the axle 81 of drum 17 causes the transverse movement of the nozzle end and the forcing of air under pressure into substantially all portions of the inlet of chute 25. Due to the comparatively steep inclination of the pge 25, there is a slight tendency for the mat to pack as it reaches the bottom of the chute, which, for example, may be substantially ten feet in height.

The lower end of the chute is arranged to feed the mat upon a horizontal belt 30 which is carried upon a series of rolls 30 and is arranged between suitable side boards 3l and below an upper presser element 32, the latter comprising a belt which inclines downwardly away from the lower end of chute 25 and has its lower run held in place by a plurality of rollers 33. The boards 31 are inclined toward each other to adord a slight compression transversely of the material, while the elements 30 and 32 together cooperate in gradually compressing the loosely uled mat into a comparatively closely knit sheet. Thus, for example, the mat entering between belts 32 and 30 may be substantially eleven inches in thickness and leaving the same may be reduced to about a quarter of this thickness.

Rolls 200 and 201 are arranged at the ends of feed belts 30 and 32 respectively and adjoining the same are succeeding pairs of rolls which are arranged materially to compress the lap as it leaves the belts. Rolls 202 and 203 receive and somewhat compress the material before cementitious binder is fed thereto. The compressed lap then passes to rolls 204 and 205 where the binder may be applied and the lap still further compressed. The first pair of rolls, i. e. rolls 202 and 203, are particularly eective in preventing any of the binder from passing back to the belts 30 and 32 so that the latter are kept clean and free from cementitious material. Rolls 204 and 205 further compress the material and force it into the bite of the wringing rolls 44 serving to distribute the binder over all of the strands and removing some of the excess binder, although a greater portion of the excess binder may be removed by the wringing rolls 44.

The means for supplying the binder to the mat of fibrous material, as shown in Fig. l, may comprise a transverse supply pipe 40 located between rolls 202 and 204 and having a plurality of small openings 42, or if desired a narrow laterally extending slot in order to provide a spray of liquid distributed across the path of the fibrous material. The liquid spray may be so directed that the binder owing upon the mat. it Gast substantially between the juxtaposed portions of the coating rolls 204 and 205, these rolls as well a the wringer rolls 44 being arranged greatly to compress the fibrous mat and thus being effective in squeezing excess binder from the same into a suitable receiving vat 46. If desired, however, the spray of binding material may be directed to the bite of rolls 202 and 203 rather than between rolls 204 and 205. The vat preferably is suitably dimensloned to extend to either side of the coating and wringer rolls so that a considerable portion of the cementitious material may drain through the reticulated material and pass into vessel 46 thereof to ensure the coating of every fibrous strand. The wetting of the fibrous material and the compression thereof causes it to tend to maintain a thickness considerably less than that which it possessed before it passed between the rolls, although upon leaving the latter it may have a thickness, for example, from ten to fifteen times as great as the minimum distance between the rolls themselves, which may be approximately one-twentieth to one-fortieth of the thickness of the mat received by the same.

The excess binder collected in the vessel 46 may pass downwardly to a pump 48 which redelivers it to the transverse pipe 40. A suitable supply tank 49 is provided with a control valve 50 and an outlet pipe 5l to permit replenishment of the liquid binder contained within vessel 46.

I have found that the arrangement of the liquid supply means and the adjoining pairs of rolls together with the provision for the flow of the liquid binder is singularly effective in permitting the light yet uniform coating of the individual strands of the fibrous mat without the formation of slugs of cementitious material in the interstices of the ultimate product and consequent waste of the binder.

As the mat leaves each pair of compressing rolls it tends to expand somewhat and due to this effect as well as the different peripheral speeds of the pairs of rolls there is a tendency toward slight relative movement of the .fibrous strands in relation to each other so that the exact region of contact of engaging strands is varied and all portions thereof are exposed to the cementitious bath; accordingly the binder becomes finally located not only about the crossed portions of engaging strands but between the same, insuring .-5

the firm binding of the strands in engagement with each other when the cementitious material sets.

Preferably the rolls 44 have a peripheral speed somewhat higher than that of the rolls 200, 201, each succeeding pair of rolls having a speed approximately 7% higher than the preceding pair,

thus permitting the rolls to have a rm frictional grip upon the mat at this stage of its journey.

While a variety of cementitious materials may be utilized for impregnating the matted strands, we prefer a solution of magnesium chloride, preferably from 15 to 25, for example about 20 on the Baume scale, which is mixed with plastic magnesia which may approximately equal the chloride in weight to provide a thin, creamy mixture which readily flows over the matted material. A plaster of Paris solution is also satisfactory for this purpose.

From the wringer rolls 44 the wet mat passes onto a slatted conveyor 58 which carries the material to a suitable cutter 60 that may be arranged in synchronism with the belts of the machine in order to sever suitable lengths of the material from the nished mat. From the belt 58 the severed mat portions, which at this stage of the process substantially lack form retaining ability, pass downwardly over an inclined series of rolls or plate 61 onto suitable press plates or molds 62.

One of the latter is shown in cross section in Fig. 4 being provided with a bottom portion 91 and an upstanding marginal portion 92, which are adapted to define one face and the edge portions respectively of the slab to be formed therein. These molds may be supported upon a roll conveyor 100 which is adapted to supply molds transversely to the path of the reticulated mat. Suitable support elements 95 have rollers 96 arranged in alignment with the support rolls of the conveyor 100, being arranged to hold a mold above the conveyor rolls 64. A drive chain 105* is arranged between the rows of rolls 64.

A suitable control mechanism is provided comprising a crank element 106 mounted on a shaft 105 and connected to a link 107 that in turn is pivotally joined to elements 95, the shaft 105 thus being rotated to permit the members 95 to be lowered so that the mold supported thereon may rest upon the rolls 64. An upstanding lug 109 upon the chain 105a is adapted to engage the edge of the mold and move the same over rolls 64 to a position below the plate 61 so that the severed mat portion may be readily guided into the mold. It is evident that the speed of chain 105EL with its drive lug 109 may be synchronized with the cutter so that the molds arrive at the lower end of plate 61 substantially at the same instant as the severed mat portions. A portable platform 110 may be arranged to receive a plurality of molds with the severed mat portions located therein, it being understood that the outstanding marginal portions 92 of the molds are so proportioned in relation to the thickness of these mat portions that the latter may be compressed to substantially four-fifths of their original thickness when the molds are superimposed with the marginal portions of one mold engaged with the bottom of the mold thereabove. For this purpose a suitable weight 120 may be lowered (or a press may be used) upon a plurality of the superimposed molds that are disposed upon a portable platform 110. The latter runs upon a suitable track 119 and may be rolled into a drying oven 121 where the material is exposed to an ordinary drying temperature until the cementitious binder has at least initially set. If desired this drying chamber may be dispensed with but the use of the same permits economy in space and time of manufacture.

After the cementitious material has set, the excelsior lumber may be taken from the molds and will be found to be form retaining.

The material formed in accordance with this present invention is characterized by the uniform distribution of the fibrous strands and the uniform yet light coating of the same with the cementitious binder. The pneumatic arrangement for ensuring the original fiuffing of the fibers is more particularly claimed in the copending application of Horatio W. Brown, No. 479,650.

We claim:

l. The method of making excelsior lumber or the like which comprises forming excelsior into a continuous uniform mat, by uniformly distributing the excelsior in a passage under air pressure, gradually and partially compressing the mat, impregnating the same with a cementitious binding solution, and holding the impregnated material under pressure until the cementitious binder has at least partially set.

2. The method of making excelsior lumber or the like which comprises forming the excelsior into a continuous uniform mat, impregnating the same with a cementitious binding solution as it is being compressed, and holding the material under pressure at least until the cementitious binder has partially set. v v

3. The method of making excelsior lumber or the like which comprises distributing the excelsior in a passage under air pressure by moving an air nozzle across the passage to form a uniform mat, impregnating the same with a cementitious binding solution, and holding the impregnated material under pressure until the cementitious binder has at least partially set.

4. The method of making excelsior lumber or the like which comprises forming the excelsior into a continuous uniform mat, impregnating the same with a cementitious binding solution as it is being compressed between rolls, and maintaining the material under pressure at least until the cementitious binder has set.

5. The method of making excelsior lumber or the like which comprises substantially uniformly distributing excelsior and confining the same in a blast of air while restraining the excelsior generally to the form of a mat, and guiding this material for downward movement obliquely of the blast so as to produce a slight tendency to compress the excelsior as it moves away from the blast.

6. The method of making excelsior lumber or the like which comprises substantially uniformly distributing excelsior generally in the form of a mat and confining the same in a blast of air while guiding the excelsior for downward movement obliquely of the blast so as to produce a tendency to compress the excelsior as it moves away from the blast, and thereafter concurrently carrying outer portions of the mat in convergent directions gradually and progressively to reduce the transverse section of the mat.

7. The method of making excelsior lumber or the like which comprises substantially uniformly distributing excelsior generally in the form of a mat and confining the same in a blast of air while guiding the excelsior for downward movement obliquely of the blast so as to produce a tendency to compress the excelsior as it moves away from the blast, and thereafter concurrently carrying opposite surfaces as well as the longitudinal edges of the mat in convergent directions gradually and progressively to reduce the transverse section of the mat.

8. The method of making excelsior lumber or the like which comprises continually forming the excelsior into a substantially continuous uniform mat, gradually and partially compressing the mat, impregnating the same with a cementitious binding solution, and further compressing the mat progressively by rolling at points spaced along the path of travel thereof so as to produce a tendency for movement of the strands of the mat relative to each other, whereby the region of contact of engaging strands may be varied and all portions thereof exposed to the cementitious solution.

9. The method of making excelsior lumber or the like which comprises continually forming the excelsior into a substantially continuous uniform mat, gradually and partially compressing the mat, impregnating the same with a cementitious binding solution, and further compressing the mat progressively by passing the mat between rolls spaced along the path or travel thereof, operating the rolls of successive pairs at progressively greater speeds to insure a er frictional grip upon the mat.

10. The method of making excelsior lumber or the like which comprises continually forming the excelsor into a substantially continuous uniform mat, gradually compressing the mat, impregnating the same during this compression with a cementitious binding solution, then relieving the met of external pressure so that it may expand and thereby improve the acoustic and insulating properties thereof, and thereafter subjecting the mat to pressure to compress it to a thickness substantially larger than its previous in. .u thickness until the cementitious binder has at least partially set and the mat is substantially form-retaining.

i1. The method of mi excelsior lumber or the like which comprises continually forming the excelsior into a substantially continuous unif -f 1": mat, gradually and partially compressing the impregnating the same with a cementitious binding solution, further compressing the mat progressively to a predetermined thickness by passing the mat between rolls spaced along the path of travel thereof, then relieving the mat of external pressure so that it may expand beyond said predetermined thickness and therebyl improve the acoustic and insulating properties thereof, and thereafter subjecting the mat to pressure to compress the same until the cementitious binder has at least partially set and the mat is substantially form-retaining with a thickness substantially greater than the predetermined thicmess.

HORATIO W. BROWN.

J. TAYLOR.

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